This invention generally relates to labeling of an item with an individualistic and readily identifiable indicia in order to provide an item identification at a location remote from that location at which the label was applied and, more particularly, to a combination explosive and method whereby explosive material is coded with information to permit an identification of the explosive material either before or after detonation of same.
The use of commercial explosives is very extensive and a comprehensive summary and discussion of same is set forth in the Blasters' Handbook, 15th. Edition (1969) by E. I. DuPont, Wilmington, Delaware. Accidental explosions have always constituted a problem with respect to a proper identification of the explosive involved. In recent years, the relatively large number of terrorists bombings have presented substantial problems, among which is the proper identification of the explosive used, and the determination of where same might have been purchased, etc. Public Law 91-452, Oct. 15, 1970, at 84 Stat. 954 requires certain records to be kept for the sale of explosive materials, but once such materials are detonated, it is a most difficult if not impossible task to trace the distribution of the explosive material prior to its detonation.
It is also desirable to label items of manufacture or items which are subjected to handling with an individualistic and readily identifiable indicia in order to provide an item identification at a location remote from that location at which the label was applied. One of the problems with such labeling is that it is extremely difficult to provide a vast number of different labels which can be scanned by some type of automatic equipment in order to facilitate automatic handling.
It is known in the prior art to apply a fluorescent material to an item and later trace a possible theft or misappropriation of such items by exposing the hands or garments of a possible suspect to ultraviolet radiation, in order to detect the presence of the fluorescent material. Such an indicia, however, normally has merely indicated the presence or lack of such fluorescent material.
In U.S. Pat. No. 3,231,738 dated Jan. 25, 1966, it is suggested to place an organic fluorescent material such as anthracene or fluorescein or rhodamine in a very finely divided state near an explosive charge or the like so that organic particles will be blown into the air with the explosion. The airborne path of the particles is then traced by placing solidified solvent in an open container in the expected path of the particles, and when the particles fall to earth and strike the solidified solvent, they can be detected by their fluorescence. All of these organic fluorescent materials act as fuels, however, and when placed in receptive proximity to the reactive atmospheres and blast effect resulting from an explosion, these fuels will completely oxidize or otherwise disintegrate, thereby completely destroying them.
U.S. Pat. No. 3,199,454 dated Aug. 10, 1965 discloses placing an organic fluorescent material such as sodium fluorescein about a small explosive charge which is to be detonated in water, in order to help control predatory fish. The explosive charge is relatively small and the presence of the water in which the charge is detonated serves to protect the fluorescein from the blast effects of the detonation so that upon striking the water, the fluorescein immediately provides an indicative fluorescent response.
It is also generally known to provide tracing or indicative materials along with such substances as drugs, and such a technique is disclosed in U.S. Pat. No. 3,341,417 dated Sept. 12, 1967. As described in this patent, an insoluble radio-opaque substance which is visible under X-rays is included with such drugs as barbiturates, in order that it may readily be determined that barbiturates have been ingested.
It is also known to apply organic fluorescent dyes as tracer materials to commercial items and this is described in U.S. Pat. No. 2,920,202 dated Jan. 5, 1960. It should be noted, however, that organic fluorescent materials exhibit an extremely broadband type of fluorescent emission and such dyes are normally used to describe one to two possibilities, namely, the presence or lack of such dye. A somewhat similar use of organic fluorescent dyes is described in U.S. Pat. No. 2,392,620, dated Jan. 8, 1946 wherein fluorescent dyes are placed in hydrocarbon products in order to show the presence or lack of undesirable crude oil in a desired crude oil.
Other uses for fluorescent dyes such as rhodamine are to embed such materials in plastic containers for the purpose of detecting possible contamination which may result from abrasion between the packaged component and the packaging film and such a technique is described in U.S. Pat. No. 3,422,265 dated Jan. 14, 1969.